/*
 * Copyright © 2002 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * California 95054, U.S.A. All rights reserved.  Sun Microsystems, Inc. has
 * intellectual property rights relating to technology embodied in the product
 * that is described in this document. In particular, and without limitation,
 * these intellectual property rights may include one or more of the U.S.
 * patents listed at http://www.sun.com/patents and one or more additional
 * patents or pending patent applications in the U.S. and in other countries.
 * U.S. Government Rights - Commercial software. Government users are subject
 * to the Sun Microsystems, Inc. standard license agreement and applicable
 * provisions of the FAR and its supplements.  Use is subject to license terms.
 * Sun,  Sun Microsystems,  the Sun logo and  Java are trademarks or registered
 * trademarks of Sun Microsystems, Inc. in the U.S. and other countries.  This
 * product is covered and controlled by U.S. Export Control laws and may be
 * subject to the export or import laws in other countries.  Nuclear, missile,
 * chemical biological weapons or nuclear maritime end uses or end users,
 * whether direct or indirect, are strictly prohibited.  Export or reexport
 * to countries subject to U.S. embargo or to entities identified on U.S.
 * export exclusion lists, including, but not limited to, the denied persons
 * and specially designated nationals lists is strictly prohibited.
 */

package org.javacc.parser;

/**
 * Describes lookahead rule for a particular expansion or expansion sequence
 * (See Sequence.java). In case this describes the lookahead rule for a single
 * expansion unit, then a sequence is created with this node as the first
 * element, and the expansion unit as the second and last element.
 */

public class Lookahead extends Expansion {

	/**
	 * Contains the list of tokens that make up the semantic lookahead if any.
	 * If this node represents a different kind of lookahead (other than
	 * semantic lookahead), then this vector contains nothing. If this vector
	 * contains something, then it is the boolean expression that forms the
	 * semantic lookahead. In this case, the following fields "amount" and
	 * "la_expansion" are ignored.
	 */
	public java.util.Vector action_tokens = new java.util.Vector();

	/**
	 * The lookahead amount. Its default value essentially gives us infinite
	 * lookahead.
	 */
	public int amount = Integer.MAX_VALUE;

	/**
	 * The expansion used to determine whether or not to choose the
	 * corresponding parse option. This expansion is parsed upto "amount" tokens
	 * of lookahead or until a complete match for it is found. Usually, this is
	 * the same as the expansion to be parsed.
	 */
	public Expansion la_expansion;

	/**
	 * Is set to true if this is an explicit lookahead specification.
	 */
	public boolean isExplicit;

}
